Nitrogen and Sulfur Co-doped Two-Dimensional Highly Porous Carbon Nanosheets for High-Performance Lithium–Sulfur Batteries
Shaukat Khan, Mazhar Ul‐Islam, Muhammad Sajjad, Iftikhar Hussain, Muhammad Idrees, Muhammad Saeed, Muhammad Imran, Muhammad Sufyan Javed
Abstract
The multiple electron redox reactions of lithium (Li) and sulfur (S), concomitantly producing a series of lithium polysulfide intermediates, generally exhibit an insufficient cycle life and poor rate performance of lithium–sulfur (Li–S) batteries. This work reports a single-step and facile synthetic strategy for fabricating uniform, micro- and mesoporous, nitrogen–sulfur co-doped carbon nanosheets anchored on the surface of reduced graphene oxide (denoted as CNS@rGO). The composite was prepared by polymerizing m-aminobenzene sulfonic acid on the surface of graphene oxide (GO) and subsequent carbonization. The obtained CNS@rGO contains uniform micro- and mesopores for better sulfur loading and further accommodation of the discharged polysulfides. Such a free-standing electrode exhibits a stable specific capacity of 1355 mA h/g at 0.1 C (100 mA g–1) and good rate performance. CNS@rGO shows promising characteristics as a high-performance cathode material for Li–S batteries. Furthermore, even at a high current density of 1 C (1 A g–1), it exhibits high storage with a capacity of 476 mA h g–1 over 300 cycles with a decay of 16.8%, which outperforms all previously reported carbon-based materials for Li–S batteries.